1. Field of the Invention
This invention relates to a building for containing human occupants in an adverse arctic or antarctic environment that are closed with respect to an environment, such as in polar regions, and that are exposed during operation to an extremely high temperature gradient, such as in polar stations in Arctic and/or Antarctic latitudes. The invention also relates to structures for containing occupants in an adverse environment that are closed with respect to an environment, such as in polar regions and that are exposed during operation to an extremely high temperature gradient, such as in polar stations in Arctic and/or Antarctic latitudes. The invention also relates to a building for containing human occupants in an adverse environment with glazing that are closed with respect to an environment, such as in polar regions, and that are exposed during operation to an extremely high temperature gradient, in particular for use as windows in polar stations in Arctic and/or Antarctic latitudes. The invention also relates to the glazing of structures that are closed with respect to an environment, such as in space, that are exposed during operation to an extremely high temperature gradient, in particular for use as windows in space stations, space vehicles, and missiles. The invention also relates to structures that are closed with respect to an environment, such as extremely high altitudes, that are exposed during operation to an extremely high temperature gradient, in particular for use as windows in airplanes, aircraft, or other vehicles being exposed to extreme temperature gradients.
2. Background of the Invention
Materials that are used in buildings for containing occupants in an adverse environment and structures for containing and protecting occupants in adverse environments, act as a barrier to adverse temperature, and pressure and thus must meet special requirements.
In buildings for containing occupants in an adverse environment and structures for containing and protecting occupants in adverse environments, as a result of atmospheric conditions which include, for example, direct solar radiation on one side while the other side is in shadow, there are extreme temperature differences. High temperature stresses can also be exerted by hot or cold air conditions. Local changes, such as rapid temperature changes, can also result in high temperature gradients across a window in a building. If inappropriate materials are used, stresses can occur that can lead to the failure of the building and/or a building""s window.
Temperature gradients also occur between the temperatures of the environments that are separated by the window. In this case, a temperature gradient or difference over the thickness of the window of xe2x88x92250xc2x0 C. or +120xc2x0 C., for example, can occur between the temperature of the structure (20xc2x0 C.) and the temperature in the environment.
Temperature gradients that are not that extreme but that can nevertheless produce high thermo-mechanical stress on the glazing occur on the windows of stations in the Arctic and the Antarctic.
There is an additional factor that has to be taken into consideration in glazing for applications. The materials used must have sufficient hardness and mechanical strength.
In general the glazing, i.e. the window, must allow a distortion-free view and must be easy to clean.
Materials that are used as windows in space stations or missiles as a barrier to the adverse temperature and pressure atmospheric conditions in space must meet special requirements.
As a result of atmospheric conditions, which include, for example, direct solar radiation on one side while the other side is in shadow, there are extreme temperature differences of xcex94 T≈370 K (sun side: +120xc2x0 C., shadow side: xe2x88x92250xc2x0 C.). High temperature stresses can also be exerted by hot or cold gas streams from missiles being launched, landing or flying past. Local changes, such as rotations or rapid temperature changes, can also result in high temperature gradients across a window. If inappropriate materials are used, stresses can occur that can lead to the failure of the window.
Temperature gradients also occur between the temperatures of the environments that are separated by the window, e.g. the inside of the space station or spacecraft and space. In this case, a temperature gradient or difference over the thickness of the window of xe2x88x92250xc2x0 C. or +120xc2x0 C., for example, can occur between the temperature of the space station (20xc2x0 C.) and the temperature in space.
Temperature gradients that are not that extreme but that can nevertheless produce high thermo-mechanical stress on the glazing occur on the windows of stations in the Arctic and the Antarctic.
There is an additional factor that has to be taken into consideration in glazing for applications in space.
Because the atmosphere can contain abrasive media, e.g. sand, dust, small meteorites, space junk etc., the materials used must have sufficient hardness and mechanical strength.
In general the glazing, i.e. the window, must allow a distortion-free view and must be easy to clean.
Materials that are used as windows in aircraft as a barrier to the adverse temperature and pressure in the environment must meet special requirements.
In aircraft, such as airplanes which fly at high and more often at extremely high altitudes, as a result of atmospheric conditions which include, for example, direct solar radiation on one side while the other side is in shadow, there are extreme temperature differences. High temperature stresses can also be exerted by hot or cold air conditions. Local changes, such rapid temperature changes, can also result in high temperature gradients across a window. If inappropriate materials are used, stresses can occur that can lead to the failure of the window.
Temperature gradients also occur between the temperatures of the environments that are separated by the window. In this case, a temperature gradient or difference over the thickness of the window of xe2x88x92250xc2x0 C. or +120xc2x0 C., for example, can occur between the temperature of the aircraft (20xc2x0 C.) and the temperature in the environment.
Temperature gradients that are not that extreme but that can nevertheless produce high thermo-mechanical stress on the glazing occur on the windows of stations in the Arctic and the Antarctic.
There is an additional factor that has to be taken into consideration in glazing for applications. The materials used must have sufficient hardness and mechanical strength.
In general the glazing, i.e. the window, must allow a distortion-free view and must be easy to clean.
The object of the invention is to create an effective glazing for buildings that are enclosed with respect to the environment in polar regions and that are exposed to an extremely high temperature gradient during operation.
Another object of the invention is to create an effective glazing for space stations and space vehicles that are enclosed with respect to the environment in space and that are exposed to an extremely high temperature gradient during operation.
Another object of the invention is to create an effective glazing for aircraft that are enclosed with respect to the environment in the air and that are exposed to an extremely high temperature gradient during operation.
The invention teaches a building for containing human occupants in an adverse Arctic or Antarctic environment, said building comprising: at least one covering element to provide at least one roof portion, at least one wall portion, and at least one floor portion, to provide an interior space to contain and protect occupants from an adverse environment about the building; the at least one covering element being configured to provided protection to occupants in an adverse Arctic or Antarctic environment; an opening to permit occupants to ingress into and egress from the building; an apparatus to close the opening from the outside environment; a window comprising a frame and at least one pane disposed in the frame; the window being configured to protect occupants from an adverse Arctic or Antarctic environment; the at least one pane comprising at least one outer pane disposed to contact the adverse environment about the building and at least one inner pane disposed toward the interior space of the building; the at least one outer pane comprising an outer surface disposed to contact the adverse environment and an inner surface facing toward the at least one inner pane; the pane exposed to the environment about the building comprising a transparent glass material; the glass material having a coefficient of thermal expansion that is minimized such that the glass material of the at least one outer pane is configured to withstand extreme temperature gradients from the outer surface to the inner surface of the at least one outer pane; at least the outer surface of the at least one outer pane being configured to have a surface roughness which is minimized, thus providing a view through the at least one pane having a distortion which is minimized and providing an easy-to-clean outer surface; the glass material being substantially free of pits and pores on at least the outer and the inner surfaces; insulation being configured to protect occupants from adverse temperature conditions from an Arctic or Antarctic environment about the building; the insulation being disposed with the at least one covering element to provide protection for occupants from adverse temperature conditions about the building; and a heating apparatus to provide heat to the space provided by the at least one covering element, the window, and the insulation in an adverse Arctic or Antarctic environment.
The invention also teaches a structure for containing human occupants in an adverse environment, the structure comprising: at least one covering element to provide a space to contain and protect occupants from an environment about the structure; a window comprising at least one pane; the at least one pane comprising at least one outer pane disposed to contact the adverse environment about the structure and at least one inner pane disposed toward the interior space of the structure; an opening to permit occupants to ingress into and egress from the structure; an apparatus to close the opening from the outside environment; the at least one pane comprising an outer pane exposed to the environment about the structure; the outer pane, exposed to the environment about the structure, comprising glass material; the glass material having a coefficient of thermal expansion that is minimized; the outer pane comprising a floated glass ceramic pane; insulation being configured to protect occupants from temperature conditions from an adverse Arctic or Antarctic environment about the structure; the insulation being disposed with the covering element to provide protection for occupants from temperature conditions from an adverse Arctic or Antarctic environment about the structure; and a heating apparatus to provide heat to the space provided by the at least one covering element, the window, and the insulation in an adverse Arctic or Antarctic environment.
The invention teaches a glazing for closed structures that are exposed to an extremely high temperature gradient.
Such extremely high temperature gradients are present, for example, on space stations, missiles for space flight or polar stations.
To guarantee high temperature strength, the glazing comprises a package of panels, the outermost panel of which, facing the environment, is made of glass ceramic.
The glass ceramic is preferably a floated glass ceramic on the basis of an aluminosilicate float glass which has a very low surface roughness, which makes possible a distortion-free view and is very easy to clean.
The glass ceramic panel is thereby transparent, so that it can be used as a window for the enclosed space in question.
It has been shown that glass ceramic can withstand the temperature gradients and temperature changes that occur. Glass ceramic is normally used for windows in the doors of furnaces and ovens in which the temperature can be up to 800xc2x0 C. The prior art also describes the use of glass ceramics as fireproof safety glass. Given the conditions in space and in the polar regions, however, the decisive factor is not the maximum temperatures but the temperature fluctuations and temperature gradients to which the material is exposed, which temperature fluctuations and temperature gradients the glass ceramic surprisingly survives.
Glass ceramic has a hard surface that is highly resistant to any abrasive objects that may be flying around. Any damage to the glass ceramic is only in the form of small pits, chips or depressions. Nevertheless, if the window does break, the pane shatters into large fragments that may or may not be held in place by the frame. In such a case, a thermally stressed panel would represent a safety risk caused by fragments flying around.
The glazing claimed by the invention typically consists not only of a single pane, but also of a package of panels. This configuration makes it easy to replace the outer glass ceramic panel without having to replace the entire package of panels. A package of panels can be constructed analogous to an insulated window or laminated glass window that is designed for thermal or acoustical insulation.
Depending on the specific application, the outer glass ceramic panel can be flat, deformed or curved.
If the glass ceramic material contains TiO2 as a nucleation agent, the glass ceramic panel also acts as a UV blocker, which is a significant advantage for the inhabitants of the enclosed space with regard to the prevention of damage caused by solar radiation.
The glass ceramic panel is preferably provided with coatings that are designed for different purposes, so that they can, for example, reduce surface reflection, reflect heat, be heated, or form a UV filter if the actual UV block is insufficient.
A conventional glass ceramic panel generally has a relatively rough surface, with a Ra of 0.35 xcexcm to 0.55 xcexcm.
Therefore, there is a relatively significant diffraction effect which interferes with a distortion-free view through the window. This rough surface also makes it difficult to clean the glass ceramic panel.
In one embodiment of the invention, an undistorted view and ease of cleaning are made possible if the glass ceramic panel has a surface that is essentially free of pores.
This absence of pores on a glass ceramic panel can either be achieved, at added effort and expense, by polishing the surface, or by using a floated glass ceramic which is realized, in one embodiment of the invention, preferably in the form of a floated glass ceramic glazing, characterized by the fact that the package of panels, including the outer glass ceramic panel, is transparent.
This floated glass ceramic has a particularly low roughness with an average roughness Raxe2x89xa60.02 xcexcm or a square average roughness Rqxe2x89xa60.01 xcexcm, and therefore has a low undesirable diffraction and is very easy to clean.
The definitions of surface roughness are explained in greater detail in DIN 4762, among other sources. For example, the average roughness Ra is the arithmetic mean or average of the absolute height differences from the center plane, or the arithmetic average of the absolute amounts of the differences between the actual or measured profile and the average profile. This average profile is calculated by laying a profile through the measured profile within a reference length, so that the sum of the surface area of the measured profile filled with material on the top and the sum of the surface areas free of materials on the bottom are equal. On the basis of DIN 4762, Rq=square average roughness, determined by means of white light interference microscopy (measurement area 0.6xc3x970.5 mm). In terms of formulas, this concept is expressed as follows:             R      a        =                  (                              "LeftBracketingBar"                          Z              1                        "RightBracketingBar"                    +                      "LeftBracketingBar"                          Z              2                        "RightBracketingBar"                    +                      "LeftBracketingBar"                          Z              3                        "RightBracketingBar"                    +          …          ⁢                      xe2x80x83                    +                      "LeftBracketingBar"                          Z              n                        "RightBracketingBar"                          )            N                  R      q        =                            (                                    Z              1              2                        +                          Z              2              2                        +                          Z              3              2                        +            …            ⁢                          xe2x80x83                        +                          Z              n              2                                )                N            
The manufacture of flat glass ceramic objects is described by the prior art.
Theoretically, all glass ceramics floated according to the methods of the prior art can be used for the manufacture of the easy-to-clean glass ceramic object claimed by the invention.
To achieve a particularly good surface quality and thus a correspondingly high ease of cleaning, the initial glass used for the glass ceramic is a float glass, in which the origin of undesirable surface defects during the floating is prevented by restricting the concentrations of Pt to  less than 300 ppb, Rh to  less than 3.0 ppb, ZnO to  less than 1.5 wt. % and SnO2 to  less than 1 wt. %, and by fining or refining the glass during the melting without using the conventional fining agents arsenic oxide or antimony oxide.
These types of glass are therefore characterized by a composition that makes it possible to prevent the formation of undesirable surface defects during floating. Floats conventionally consist of the melting chamber or hot end, in which the glass is melted and fined or refined, an interface that provides the transition from the oxide atmosphere in the melting chamber into the reducing atmosphere in the rest of the system, and the float portion, in which the glass is shaped by pouring it onto a molten metal, generally Sn, in a reducing atmosphere of forming gas. The glass is formed by allowing it to flow out smoothly onto the Sn bath and by top rollers that exert a force on the surface of the glass. During the transport on the metal bath, the glass cools, and at the end of the float portion, it is lifted off and transferred into a cooling furnace, lehr or annealing furnace/oven.
During the formation of the glass surface and the transport through the float, interactions between the glass and the float atmosphere or the Sn batch can result in undesirable surface defects.
If the glass contains more than 300 ppb Pt or more than 30 ppb Rh in dissolved form, metallic precipitations of Pt or Rh particles can form as a result of the reducing conditions in the glass surface, and these particles can serve as effective seeds for large high quartz or beta quartz mixed crystals up to 100 mm, and thus cause undesirable surface crystallization. These materials are used in, among other things, electrodes, linings, agitators, transport tubes, valve gates etc. In plants for the performance of the method for the manufacture of the glass ceramic described above, to prevent the formation of surface crystals, therefore, components that contain Pt or Rh are completely avoided, and are replaced by ceramic materials, or the conditions in the melting chamber or in the interface are realized so that the above-mentioned concentrations are not exceeded.
The ZnO concentration is restricted to 1.5 wt. %. It has been shown that under the reducing conditions of the floating, the zinc is depleted in the surface of the glass. It is thereby assumed that the zinc is partly reduced on the surface of the glass, whereupon it vaporizes as a result of the higher vapor pressure of Zn compared to Zn2+ in the float atmosphere. In addition to the evaporation and deposition of the Zn in colder spots, which are undesirable for the operation of the float, the uneven distribution of the Zn in the glass also participates in the origin of critical crystal bands close to the surface. These crystal bands of large high or beta quartz mixed crystals originate in the vicinity of the surface where the Zn concentration in the glass has risen back close to the initial value. It is therefore appropriate to keep the initial value low from the start.
The concentration of SnO2 in the glass is restricted to less than 1 wt. %. As a result of the action of the reducing conditions in the float portion, the SnO2 is partly reduced, especially in the surface of the glass. Surprisingly, small metal Sn spheres form in the glass in the immediate surface of the glass, and, although they can easily be removed during cooling or cleaning, they leave behind spherical holes or pits or depressions that are extremely undesirable for the intended use of the glass.
These small spheres can be prevented if the concentration of SnO2 is very low.
The above-mentioned initial glasses are fined or refined without using the fining agents arsenic oxide and/or antimony oxide which are conventional for glass from the Li2Oxe2x80x94Al2O3xe2x80x94SiO2 system. Under the action of the reducing conditions during floating, the above mentioned fining agents in particular are reduced directly on the surface of the glass and form undesirable and visible metallic coatings. The removal of these coatings, which are aesthetically and toxicologically undesirable, requires grinding and polishing and is disadvantageous for economic reasons. To prevent the formation of the coatings, it is therefore appropriate to achieve a low seed number or number of seeds or number of bubbles by adding at least one alternative chemical fining agent, such as SnO2, CeO2, sulfate compounds, or chloride compounds, for example, preferably 0.2-0.6 wt. % SnO2, to the molten glass. Alternatively, the molten glass can also be fined physically, e.g. by means of underpressure or by means of high temperature  greater than 1750xc2x0 C. Thus the required seed quality or number of bubbles can be achieved by means of alternative fining agents and/or alternative fining methods.
During the ceramization, care must be taken to avoid any adverse effect on the low roughness values achieved by floating, for example, by conducting the ceramization vertically or by an air-cushion ceramization, i.e. generally without any contact between the glass object being ceramized and a substrate.
Special advantages with regard to a very low surface roughness of the glass ceramic are achieved by a floated, ceramized aluminosilicate glass with the following composition in wt. % on an oxide basis: Li2O comprising three and two tenths to five weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; Na2O comprising zero to one and five tenths weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; K2O comprising zero to one and five tenths weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; xcexa3Na2O+K2O comprising two tenths to two weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; MgO comprising one tenth to two and two tenths weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; CaO comprising zero to one and five tenths weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; SrO comprising zero to one and five tenths weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; BaO comprising zero to two and five tenths weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; ZnO comprising zero to less than one and five tenths weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; Al2O3 comprising nineteen to twenty-five weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; SiO2 comprising fifty-five to sixty-nine weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; TiO2 comprising one to five weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; ZrO2 comprising one to two and five tenths weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; SnO2 comprising zero to less than one weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; xcexa3TiO2+ZrO2+SnO2 comprising two and five tenths to five weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; P2O5 comprising zero to three weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range.
In a second realization, the glass in one particularly preferred embodiment has a composition, in wt. % on an oxide basis, of: Li2O comprising three and five tenths to four and five tenths weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; Na2O comprising two tenths to one weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; K2O comprising zero to eight tenths weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; xcexa3Na2O+K2O comprising four tenths to one and five tenths weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; MgO comprising three tenths to two weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; CaO comprising zero to one weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; SrO comprising zero to one weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; BaO comprising zero to two and five tenths weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; ZnO comprising zero to one and weight percent within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; Al2O3 comprising nineteen to twenty-four weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; SiO2 comprising sixty to sixty-eight weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; TiO2 comprising one to two weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; ZrO2 comprising one and two tenths to two and two tenths weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; SnO2 comprising zero to six tenths weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; xcexa3TiO2+ZrO2+SnO2 comprising three to four and five tenths weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range; P2O5 comprising zero to two weight percent and within the range percentages in tenth of percent steps such that any tenth of a percent may be a limit of a diminished range.
This glass is used with particular advantage for the manufacture of the glass ceramic object claimed by the invention, because the corresponding surface is very easy to clean.
The above-discussed embodiments of the present invention will be described further herein below. When the word xe2x80x9cinventionxe2x80x9d is used in this specification, the word xe2x80x9cinventionxe2x80x9d includes xe2x80x9cinventionsxe2x80x9d, that is, the plural of xe2x80x9cinventionxe2x80x9d. By stating xe2x80x9cinventionxe2x80x9d, the Applicants do not in any way admit that the present application does not include more than one patentably and non-obviously distinct invention, and maintain that this application may include more than one patentably and non-obviously distinct invention. The Applicants hereby assert that the disclosure of this application may include more than one invention, and, in the event that there is more than one invention, that these inventions may be patentable and non-obvious one with respect to the other.